1. Field of Invention
The present invention relates to reeled well tubing systems used in well operations.
2. Description of Prior Art
It has been an increasingly accepted practice for a variety of reasons to store and transport well tubing, particularly for petroleum exploration and production operations, on large reels. The reeled tubing was transferred from the reel by a tubing injector into and out of the well through the well drill floor. The well tubing was subject to a number of bending events as the tubing was straightened and unbent from the reel for injection into the well, or then again bent several times as it was extracted from the well for storage on the reel.
The service life of reeled tubing was typically determined by the number of bending events to which the tubing was subjected. To the extent that the type and degree of bending to which the tubing was subjected could be reduced, the service life of the tubing would have been extendable. However, so far as is known, the diameter of the storage reel and the length and nature of tubing travel between the reel and the injector have heretofore been the primary factors in determining the type and extent of bending events on reeled well tubing.
Another consideration in the use of reeled tubing has been the amount of space required. Typically, the tubing storage reel has been kept a considerable distance from the injector. This has been done to control an angle, known as the "fleet angle," between the plane of longitudinal axis of the tubing leaving the reel and the plane of the rotational axis of the reel. If the fleet angle was not properly regulated, the tubing did not wrap and unwrap properly on the storage reel.